NIF’s 500-TW Laser Shot Sets Record

Photonics.comJul 2012
LIVERMORE, Calif., July 17, 2012 — The National Ignition Facility’s (NIF’s) 192-beam laser system delivered a record-breaking 500 TW of peak power and 1.85 MJ of ultraviolet laser light to its target, validating the NIF’s laser performance specifications set in the late 1990s.

Combining extreme levels of energy and peak power on a target in NIF is a critical requirement for achieving one of the great challenges of physics — igniting hydrogen fusion fuel in the laboratory and producing more energy than that supplied to the target.

After 15 years of preliminary work, the NIF’s 192 lasers delivered more than 500 TW of peak power — 1000 times more power than the US uses at any instant in time — and 1.85 MJ of ultraviolet light — about 100 times what any other laser regularly produces — onto a 2-mm-diameter target. The total energy matched the amount requested by shot managers to within better than 1 percent. Additionally, the beam-to-beam uniformity was within 1 percent, making NIF not only the highest energy laser of its kind but also the most precise and reproducible.

The preamplifiers of the National Ignition Facility are the first step in increasing the energy of laser beams as they make their way toward the target chamber. NIF recently achieved a 500-TW shot — 1000 times more power than the US uses at any instant in time. (Images: Damien Jemison/LLNL)
"NIF is becoming everything scientists planned when it was conceived over two decades ago," said its director, Edward Moses. "It is fully operational, and scientists are taking important steps toward achieving ignition and providing experimental access to user communities for national security, basic science and the quest for clean fusion energy."

NIF is operating routinely at unprecedented performance levels. The July 5 shot was the third experiment in which total energy exceeded 1.8 MJ on the target. On July 3, scientists achieved the highest-energy laser shot ever fired, with more than 1.89 MJ delivered to the target at a peak power of 423 TW. A shot on March 15 set the stage for the July 5 experiment by delivering 1.8 MJ for the first time with a peak power of 411 TW. (See: NIF Fires Record-Setting Laser Shot)

Concerns about achieving these levels of extreme laser performance on NIF centered in part on the quality of optics that existed in the late 1990s, which could not withstand laser light this intense. LLNL scientists worked closely with industrial partners to improve manufacturing methods and drastically reduce defects. They also developed in-house procedures to remove and mitigate small amounts of damage that resulted from repeated laser firings.

A view of a cryogenically cooled NIF target as “seen” by the laser through the hohlraum’s laser entrance hole. In ignition experiments, the hydrogen in the fuel capsule must be compressed to about 100 times the density of lead.
NIF has influenced the design of new giant laser facilities that are being planned or built in the UK, France, Russia, Japan and China.

The facility is located at Lawrence Livermore National Laboratory and is funded by the National Nuclear Security Administration, a semi-autonomous agency within the US Department of Energy responsible for enhancing national security through the application of nuclear science.

"Already the most incredibly tightly controlled and most energetic laser in the world, it is remarkable that NIF has achieved the 500-TW milestone — quite a significant achievement," said Dr. Raymond Jeanloz, professor of astronomy and earth and planetary science at the University of California, Berkeley. "This breakthrough will give us incredible new opportunities in studying materials at extreme conditions."

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